The Electrophysiology Core will provide centralized services for electrophysiological studies, including preparation of in vitro brain slices, patch-clamp recordings, immunohistochemistry, and the associated image and data analysis. Project 3 (Scammell) and Project 5 (Chamberlin) will use this Core facility. Project 3 will use the services of the Core to examine how orexin and dynorphin increase forebrain activity. Specifically, these experiments will define the pre- and post-synaptic effects and the mechanism through which these neurotransmitters affect cortically-projecting neurons in the basal forebrain. We will also determine the peptide receptors and conductances involved in these responses. Project 5 will use the Electrophysiology Core to determine whether neurons of the Kolliker-Fuse (KF) nucleus are chemosensitive. We will determine which KF neurons are intrinsically responsive to changes of pH, and we will identify the mechanisms underlying these responses. These Projects will benefit from the expertise and many shared resources of the Core.